Rimantadine



Better Known as: Flumadine

 * Marketed By: Forest Labs


 * Major Indication: Influenza Infection


 * Drug Class: M2 Proton Channel Inhibitor
 * Date of FDA Approval (Patent Expiration): 1993 (2001)


 * 1994 Sales: N/A
 * Importance: One of the the first treatments for Influenza Infections. Since 1994, nearly 100% of influenza viruses had developed resistance to rimantadine, and it is no longer recommended as a treatment for the flu.
 * See Pharmaceutical Drugs for more information about other drugs and disorders.

Mechanism of Action
The Influenza A Virus viral envelope is dotted with various ion channels including M2 Proton Channels. The M2 protein plays a critical role in the life cycle of the Influenza virus. It enables hydrogen ions to enter the virion form the endosome. The result of this is a more acidic environment within the virus, causing dissociation of the viral matrix protein M1 from the ribonucleoprotein RNP. Dissociation of the viral matrix protein is a crucial step in uncoating of the virus and exposing its contents to the cytoplasm of the host cell, allowing the virus to hijack the cellular machinery to replicate. Rimantadine binds in multiple places outside the pore formed by the M2 protein, utilizing residues Leu 43, Leu 40, Asp 44, Arg 45, Trp 41 from one chain and Ile 42 from the neighboring chain. This effectively disables the protein from transferring protons into the viral particle.